A new profile has been added to the list of Triumph motorcycle models on this site: The Bonneville T120RT (1970). Needing to increase the capacity of the 650cc Bonneville T120 to compete in the AMA 750 cc class, Tricor (Triumph's East Coast US distributor) came up with a conversion kit. The AMA rules required a minimum of 200 machines to be on sale to the public before a machine could be considered for entry into races for the 750cc class. Triumph themselves were not interested in increasing the Bonneville to 750cc, and anyway they had their hands full with the Trident T150. So Rod Coates (Tricor Service Manager), along with Sonny Routt, developed a conversion kit that could be fitted to the 650cc motor.
The kit comprised a cast iron cylinder block, pistons, and ring set. It was fitted to brand new machines by partially in-crating them and replacing the 650 blocks with the kit. To identify the machines, a 'T' was added after the T120R engine number designation. It was only added to the engine number, not the frame number. Any purchasers also had to sign a disclaimer that the machine was sold as only for racing and competition.
It wasn't long before Triumph themselves found out about the kit, and Peter Thornton (busy merging BSA and Triumph) summarily dismissed Rod Coates. As a result only 204 machines were produced, but that was enough to go racing.
The only way to really tell if you have a valid T120RT is to strip the top end and measure the barrels and pistons. There have been a number of forgeries recorded.